"Once we went behind, it turned into an uphill struggle," said former Milan player Gattuso.

Bryan Cristante opened the scoring after 32 minutes for Atalanta with Josip Ilicic scoring the second on 71 minutes.

"What we are doing is not enough, we must become a team. We lack determination, hunger and grit. I also think we should stop making comparisons with the past. I see a team scared and worried," added Gattuso.

Gattuso's side next play Inter Milan in a potentially fiery Italian Cup quarter-final tie on Wednesday, with their city rivals also reeling after a second consecutive defeat.

"We don't have time to let our heads drop or create excuses, there's Inter in the Italian Cup and we must face it with the greatest dignity," said Milan sporting director Massimiliano Mirabelli.

"'Rino' is a great man, a great coach. We knew that we were facing a lot of problems and he lives Milan to the full, caring so much about this side.

"During these difficult times, it's important to be men, stick together and work to get the ship back into the harbour safely."